VrLib: A Designer Oriented Interaction and 3D User Interface Library

Three-dimensional (3D) virtual environments (VEs) are collaboration platforms where group members are represented as avatars and interact in a customizable simulated world. Research from cognitive psychology has shown that it is possible to manipulate nonconscious cognition and behavior through “priming,” a well-known phenomenon in which words and images are used to activate desired concepts in participants’ minds. Our goal in this was to investigate whether priming during the task execution (called contextual priming) using 3D objects in the VE can improve brainstorming performance. To investigate this, we conducted two studies. The first used priming objects specifically related to the task topic and the second used priming objects related to creativity, in general. Compared to VEs without 3D priming objects, our results show that when groups brainstormed in the VEs designed with 3D priming objects, they generated better quality ideas as well as a greater breadth and depth of ideas. Thus, the 3D priming stimuli incorporated in a VE enhances brainstorming, which indicates that the design of VE has a direct effect on team brainstorming performance. Our results also show that target concept activation and task absorption act as the underlying mechanisms, partially mediating the relationship between the design of the VE (i.e., the presence or absence of priming objects) and performance outcomes.

We describe a design for a collaborative virtual learning environment (VLE) to support massively multi-user and multi-institutional learning communities. This architecture extends Croquet to encompass a tier of distributed cache servers that allow intelligent caching and pre-fetching of objects, scene definitions, and textures. The design also provides for interactivity servers tied to specific regions in the VLE. Interactivity servers provide persistence for neighborhoods, coordinate modification and transient phenomena for locales in the virtual space, and ensure trust relations by managing user identification, authentication, and authorization via integration with existing institutional authentication infrastructure. This system supports real-time interactions that promote a self organizing, interdisciplinary knowledge sharing system within a scalable VLE in a manner that ensures accountability and trust relations.

An appropriate user interface to collect human demonstration data for deformable object manipulation has been mostly overlooked in the literature. We present an inter-action design for demonstrating cloth folding to robots. Users choose pick and place points on the cloth and can preview a visualization of a simulated cloth before real-robot execution. Two interfaces are proposed: A 2D display-and-mouse interface where points are placed by clicking on an image of the cloth, and a 3D Augmented Reality interface where the chosen points are placed by hand gestures. We conduct a user study with 18 participants, in which each user completed two sequential folds to achieve a cloth goal shape. Results show that while both interfaces were acceptable, the 3D interface was more suitable for understanding the task, and the 2D interface was suitable for repetition. Results also found that fold previews improve three key metrics: task efficiency, the ability to predict the final shape of the cloth, and overall user satisfaction.

This paper presents a distributed, multi-user virtual reality testbed for a mobile robot. The main components of the testbed include user interface, networking, simulation and robot control. The user interface is implemented as a combination of a virtual environment and a standard graphical user interface (GUI). The virtual environment is developed using the Virtual Reality Modeling Language (VRML) and it corresponds to the laboratory environment where the robot is placed and tested. The standard GUI is implemented using Java Programming language. The World Wide Web (WWW) browser is used to integrate the virtual environment (embedded VRML) and the standard GUI (Java applet) in a single user interface. Users can access a dedicated WWW server and download the user interface. Networking component (communication among users and robots) is implemented using the Distributed Interactive Simulation (DIS) protocol. The existing robot development system has been utilized to provide simulation capabilities. A separate stand-alone Java application has been developed to communicate and control the robot using a wireless Ethernet link. In addition to user's direct control, control algorithms (e.g. fuzzy logic based) can be used to replace the user. A Nomad200 mobile robot has been used for initial measurements and evaluations of the testbed.

Dear SCPE Reader, We present a selection of papers which are extensions of papers presented at the 7-th International Symposium on Parallel and Distributed Computing, 1–5 July 2008, in Krakow, Poland. The motivation for publishing the selection in the SCPE Journal was, on the one hand, to present the flavour of the research reported at the conference and on the other hand to present some of the most relevant topics currently focused on the research on parallel and distributed computing in general. The selection contains only 6 papers out of about 60 presented at the conference, and thus, is far from covering all relevant topics represented at the ISPDC 2008. This is because not all of the invited authors were patient enough to accept a fairly long paper publishing process. Nevertheless, we hope that the presented papers will bring you closer to the research covered by the ISPDC conferences and will encourage you to participate in future ISPDC editions. The first paper ``The Impact of Workload Variability on Load Balancing Algorithms'' is by Marta Beltran and Antonio Guzman from King Juan Carlos University in Spain. It concerns an important topic of load balancing in cluster systems, namely adaptativity of the load balancing algorithms to changes of the workload in the system. Adequate accounting for additional load in the hosting system is of great relevance for correct optimization effects. The paper presents a thorough formal analysis of the workload variability metrics and their influence on the quality of load balancing algorithms. Four basic activities appearing in load balancing algorithms are identified, and based on them some algorithmic solutions are proposed to correctly deal with workload variability in system load balancing. The problem of dynamic load balancing algorithms robustness has been discussed. Two different robustness metrics sensitive to the applied type of opimization: local task-oriented or a global one enable selecting task remote execution or migration as load balancing operations. The proposed approach is illustrated with experiments. The second paper ``Model-Driven Engineering and Formal Validation of High-Performance Embedded Systems'' is by Abdoulaye Gamatie, Eric Rutten, Huafeng Yu, Pierre Boulet, Jean-Luc Dekeyser, from University of Lille and INRIA in France. The paper is concerned with a very advanced methodology of designing correct parallel embedded systems for intensive data-parallel computing. In their previous research, the authors of the paper designed the GASPARD embedded system design framework. It is based on the hardware/software co-design approach through model-driven engineering. The framework is based on an UML-like model specification language in which hardware and software elements are modelled using a component approach with special mechanisms for repetitive structures. This paper tries to combine the modelling framework of GASPARD with the mechanisms of synchronous languages to achieve design verifiability provided for such languages. The paper shows how GASPARD models can be translated into synchronous models based on data flow equations in order to formally check their correctness. The proposed approach is illustrated with an example of a video processing system. The third paper ``Relations Between Several Parallel Computational Models'' is by Stephan Bruda and Yuanqiao Zhang from Bishop’s University in Canada. The paper is concerned with theoretical aspects of shared memory systems described by the parallel random access machine PRAM model and aims in studying performance properties of different types of PRAM systems. The attention is focussed on analysing the computational power of two more sophisticated PRAM models (Combining CRCW and Broadcast Selective Reduction), which include data reduction in case of concurrent writes. The paper shows that these two models have equivalent computational power, which is a new result comparing the existing literature. The performance of both models applied to reconfigurable multiple bus machines was studied as a possible architectural solution for current VLSI processor implementations. It was shown that in such systems under reasonable assumptions concurrent-write does not enhance performance comparing the exclusive-write model. Another result important for the VLSI technology is that the Combining CRCW PRAM model (in which data of concurrent writes are arthmetically or logically combined before write) and the exclusive-write on directed reconfigurable busses perform in equivalent way under strong real-time requirements. The fourth paper ``Experiences with Mesh-Like Computations Using Prediction Binary Trees'' is by Gennaro Cordasco, Biagio Cosenza, Rosario de Chiara, Ugo Erra and Vittorio Scarano from the University ``degli Studi'' of Salerno and the University ``degli Studi della Biasilicata'' of Potenza in Italy. The paper concerns optimization methods for mesh-like computations in clusters of processors. The computations are perfomed assuming a phase-like program execution control using a tiling approach which reduces inter-processor communication. A temporal coherence is also assumed, which means that task sizes provide similar execution times in consecutive phases. Temporary coherent computations are structured in a Prediction Binary Tree, in which leaves represent computing tiles to be mapped to processors. A phase-by-phase semi-static load balancing is introduced to the scheduling algorithm. The scheduling algorithm is equipped with a predictor, which estimates the computation time of next phase tiles based on previous execution times and modifies the tiles to achieve balanced execution in phases. For this, two heuristics are used to leverage on data locality in processors. The proposed approach is illustrated by the example of interactive rendering with Parallel Ray Tracing algorithm. The fifth paper ``The Influence of the IBM pSeries Servers Virtualization Mechanism on Dynamic Resource Allocation in AIX 5L'' is by Maciej Mlynski from ASpartner Limited in Poland. The paper concerns a very up-to-date problem of system virtualization and presents the results of research carried on IBM pSeries servers. IBM is strongly developing the virtualization technique especially on IBM pSeries servers enabling an improved and flexible sharing of system resources between applications. The paper investigates novel facilities for dynamic resource management such as micro-partitioning and partition load manager. They enable dynamic creation of workload logical partitions of system resources and their dynamic mangement. It includes run-time resource re-alocation between logical partitions including setting of sharing specifications as well as run-time adding/removing/setting parameters of resources in the system. It remains an open question how to properly tune parameters of the operating system using the provided virtualization facilities to obtain the best efficiency for a given application program. The paper presents the results of experiments which study the effects of tuning the disk subsystem parameters under the IBM AIX 5L operating system with the use of the provided virtualization facilities on the resulting application execution performance. The results show that even small deterioration in the resource pool status requires an immediate adaptation of the operating system parameters to maintain the required performance. The sixth paper ``HeteroPBLAS: A Set of Parallel Basic Linear Algebra Subprograms Optimized for Heterogeneous Computational Clusters'' is by Ravi Reddy, Alexey Lastovetsky and Pedro Alonso from University College Dublin in Ireland and Polytechnic University of Valencia in Spain. The paper concerns the methodology for parallelization of linear algebra computations for execution in heterogeneous cluster environments. The design of the HeteroPBLAS library (Parallel Basic Linear Algebra Subprograms) for heterogeneous computational clusters is presented. The main contribution of the paper is the automation of the parallelization and optimization of the PBLAS, which is done by means of a special user interface and the underlying set of functions. An important element is here a performance model that is based on program code instrumentation, which determines parameters of the application and the executive heterogeneous platform relevant for execution performance of parallel code. The parameter values specified for or returned by execution of the performance model functions are next used for generation and optimal mapping of the parallel code of the library subroutines. The proposed approach is illustrated by experimental results of execution of optimized HeteroPBLAS programs on homogeneous and heterogeneous computing clusters. Marek Tudruj

The thesis presents the research of inventing a novel and natural spatial human-system interface – MagicPad that is to be used in a fully immersive virtual environment. With the advance in Virtual Reality (VR) technology, modern computer systems are capable of immersing users into a synthetic environment. Instead of sitting in front of the monitor, virtual objects are surrounding the users in an immersive VR system and therefore the traditional human-computer interfaces such as mouse and keyboard are no longer appropriate / fit for such purpose. Since then, researchers have been actively seeking new means of human-computer interaction in the three-dimensional space. The objective of this research is to innovate, design and build a novel spatial user interface for immersive VR systems by investigating and identifying the core elements of an intuitive and effective spatial user interface. The research methodology adopted is based on the quantitative research methods where the perception and interaction of human subjects with a synthetic virtual environment such user interfaces are collected to investigate the performance and effectiveness of the spatial user interface. The key elements of an intuitive and effective spatial user interface are first identified and the design concept of the MagicPad user interface prototype is then established. In order to realize the overall design and study the concept of the spatial human-system interface, an immersive Virtual Reality system imseCAVE, which serves as the test bed of the MagicPad user interface is designed and built from scratch. In this research, the MagicPad interface is implemented and quantitative user evaluations with the imseCAVE are carried out to draw conclusion and future research directions in the field of Virtual Reality and 3D User Interfaces.

The COMSON project (COupled Multiscale Simulation and Optimization in Nanoelectronics) is a Marie Curie Research Training Network (RTN) supported by the European Commission within the 6th Framework Research Programme of the EU. One of the outcomes of the COMSON project is the e-learning system linked to the Demonstrator Platform (DP). This framework is intended for researches in the Microelectronics, Physics and Applied Mathematics fields. It is also intended for industries and expert technical personnel. The main aim of the project is to provide an effective training to students and young researchers with a hands-on experience with the DP, which comprises coupled simulation of devices, interconnects, circuits, electromagnetic (EM) fields and thermal effects in one single framework. Furthermore, the project has a Virtual Working Place system in which it is possible to share experiments and results among the partners. As this domain of knowledge is very complex - there are strong requirements in Industry in order to train young researchers and improve the know-how in a process of continuous education in these topics - the approach we propose overcomes the traditional difficulties of delivering contents, providing the user with a transparent interface, which hides the mathematical technalities. The user has only to follow a procedure by using a visual, tactile and explorative interface. It allows a graphical access to a preset library of models in the form of equations and algorithms for model manipulation. Furthermore, in this approach the researcher can define new models and algorithms by means of a constructivist metaphor. Finally, this method permits an easy control of the DP simulation function, together with a complete monitoring and data analysis facility.

Virtual environments and other applications of computer-generated scenes are emerging. This increases the demand for tools for efficient creation of the virtual worlds and interaction with the components in the virtual world. Introduction of immersiveness in the modeling process seems promising, but a number of issues related to immersive modeling still have to be investigated. The authors present a framework for an immersive modeling system with a hybrid 2D/3D user interface. The designer is immersed in the design space, which improves his awareness of the design objects under consideration. 2D and 3D human-computer interaction techniques are combined in the user interface to improve the efficiency of the modeler. While 3D interaction is natural for a number of design tasks, 2D interaction is particularly helpful for interaction with menus and dialog boxes, for precise manipulations and for editing operations that are subject to constraints.

The possibilities offered by digital tools for visualization, distribution, and storage of educational resources, as well as for interaction and communication between professors and students, are broadly acknowledged. However, the role of graphical user interface design in digital educational environments has still not been sufficiently valued. In this paper, we support the idea that the arrangement, distribution, and visual attributes of graphic elements (i.e., what in the field of art is called composition) in the design of the graphic interface of educational environments is not only a matter of aesthetics. It also results in better understanding of the educational message and in a significant reduction of cognitive overload in the learning process. The relationship between visual stimuli and cognitive processes that favour learning is highlighted.

Personalized graphical user interfaces have the potential to reduce visual complexity and improve efficiency by modifying the interface to better suit an individual user’s needs. Working in a personalized interface can make users faster, more accurate and more satisfied; in practice, however, personalization also comes with costs, such as a reliance on user effort to control the personalization, or the introduction of spatial instability when interface items are reorganized automatically. We conducted a series of studies to examine both the costs and benefits of personalization, and to identify techniques and contexts that would be the most likely to provide an overall benefit. We first interviewed long-term users of a software application that provides adaptable (usercontrolled) personalization. A design trade-off that emerged is that while personalization can increase the accessibility of features useful to a user’s current task, it may in turn negatively impact the user’s awareness of the full set of available features. To assess this potential trade-off, we introduced awareness as an evaluation metric to be used alongside more standard performance measures and we ran a series of three studies to understand how awareness relates to core task performance. These studies used two different measures to assess awareness, showing that personalization can impact both the recognition rate of unused features in the interface and user performance on new tasks requiring those features. We investigated both adaptive (system-controlled) and adaptable personalization techniques to help us understand the generalizability of the awareness concept. In addition to introducing and incorporating awareness into our evaluations, we studied how specific contextual and design characteristics impact the user’s experience with adaptive interfaces. In one study, we evaluated the impact of screen size on performance and user satisfaction with adaptive split menus. Results showed that the performance and satisfaction benefits of spatially reorganizing items in the interface are more likely to outweigh the costs when screen size is small. We also introduced a new adaptive personalization technique that maintains spatial stability, called ephemeral adaptation, and evaluated it through two studies. Ephemeral adaptation improves performance over both another closely related adaptive technique and a traditional interface.

This paper analyzes and evaluates different types of interactions in educational software that uses three-dimensional (3D) interactions and visualization technologies, with a focus on accessibility in such environments. To determine the accessibility parameters based on 3D user interactions, a two-phase pilot study was conducted. In the first phase, the GeometryGame research instrument was tested, in which objective metrics were collected. In the second phase, subjective metrics were collected in the form of participants’ opinions on certain aspects of accessibility and interactions implemented in the GeometryGame. The most important interaction parameters were evaluated, including the size of the objects, the presence of distractions, the intuitiveness of the user interface, and the size and distance of the interaction elements from the virtual hand. The results provide insight into user preferences and highlight the importance of customizing the user interface to ensure effective and accessible 3D interactions. Based on objective measurements and subjective user feedback, recommendations were developed to improve the accessibility of educational software that supports 3D interactions; to increase usability, reliability, and user comfort; and to enhance future research in this area.

In this paper, we present a study to show that matching the dimensionality of interaction techniques with the dimensional demands of the task results in an interface that facilitates superior performance on interaction tasks without sacrificing performance on 2D tasks in favor of 3D tasks and vice versa. We describe the concept of dimensional congruence and how to identify the dimensional characteristics of a task so that appropriate interaction techniques can be applied. We constructed a prototypical application in a Virtual Environment Enclosure (VEE) using a hand-held device to show how this might be done in this type of apparatus. We then describe a study that evaluates both 2D and 3D tasks as performed using typical 2D and 3D interaction techniques. Results show that an appropriate mix of 2D and 3D interaction techniques is preferred over exclusive use of one or the other. The challenge lies not in selecting independent interaction techniques for specific tasks, but rather in constructing an overall interface that mixes 2D and 3D interactions appropriately.

The subject of the study is the features of the organization of virtual reality interfaces. The author examines in detail such aspects of the topic as user involvement in the virtual environment, various ways and scenarios of user interaction with virtual reality, user security in the virtual environment, as well as such a phenomenon as cyberbullying and ways to prevent it. The study also considers the use of voice control as an alternative to manual. Particular attention in this study is paid to the classification of virtual reality interfaces, among which sensory interfaces, interfaces based on user motor skills, sensorimotor interfaces, interfaces for modeling and developing virtual reality are distinguished and considered in detail. The main conclusion of the study is that the virtual reality interface should be designed taking into account the ergonomics of users to prevent muscle fatigue and cyber-pain. In addition, it is very important to ensure the user's safety when designing virtual environment interfaces: using the virtual reality interface should not lead to injury to the user. To create an ergonomic and secure virtual reality interface, a combination of different types of interfaces is often required, through which the user can access an alternative control method or improved navigation. A special contribution of the author to the study of the topic is the description of the classification of virtual reality interfaces.

Analysis of raw volume data generated from different scanning technologies faces a variety of challenges, related to search, pattern recognition, spatial understanding, quantitative estimation, and shape description. In a previous study, we found that the Volume Cracker (VC) 3D interaction (3DI) technique mitigated some of these problems, but this result was from a tethered glove-based system with users analyzing simulated data. Here, we redesigned the VC by using untethered bare-hand interaction with real volume datasets, with a broader aim of adoption of this technique in research labs. We developed symmetric and asymmetric interfaces for the Bare-Hand Volume Cracker (BHVC) through design iterations with a biomechanics scientist. We evaluated our asymmetric BHVC technique against standard 2D and widely used 3D interaction techniques with experts analyzing scanned beetle datasets. We found that our BHVC design significantly outperformed the other two techniques. This study contributes a practical 3DI design for scientists, documents lessons learned while redesigning for bare-hand trackers, and provides evidence suggesting that 3D interaction could improve volume data analysis for a variety of visual analysis tasks. Our contribution is in the realm of 3D user interfaces tightly integrated with visualization, for improving the effectiveness of visual analysis of volume datasets. Based on our experience, we also provide some insights into hardware-agnostic principles for design of effective interaction techniques.

Desktop environments represent a powerful user interface and have been used as the de facto standard human-computer interaction paradigm for over 20 years. But the rising demand of 3D applications dealing with complex datasets exceeds the capabilities of traditional interaction devices and two-dimensional displays. Such applications need more immersive and intuitive interfaces. In order to be accepted by the users, technology-driven solutions that require inconvenient instrumentation, e.g., stereo glasses or tracked gloves, should be avoided. Autostereoscopic display environments equipped with tracking systems enable humans to experience virtual 3D environments more naturally, for instance via gestures, without having to use annoying devices. However, currently these approaches are used only for specially designed or adapted applications. In this paper we introduce new 3D user interface concepts for such setups which require minimal instrumentation of the user and can be integrated easily in everyday working environments. We propose an interaction framework which supports simultaneous display of and simultaneous interaction with both monoscopic as well as stereoscopic contents. We identify the challenges for combined mouse-, keyboard- and gesture-based input paradigms in such an environment and introduce novel interaction strategies.KeywordsHCIautostereoscopic display environments3D user interfaces